Hemisynthetic derivatives of oleuropein

Oleuropein (1), the major constituent of Olea europea leaves, has been found to possess a large range of pharmacological properties. In this context, because of the non-specificity of these effects, different analogs have been synthesized from 1 in order to study structure/activity relationships. Therefore, the hydroxylation degree of the hydroxytyrosol part has been modified along with the length of the connecting chain. New alkyl esters, amide and thioesters derivatives have also been synthesized. These compounds were prepared by esterification/amidation of 3 which was obtained by saponification of 1 followed by acetylation of the glucose part. The final selective deprotection of the acetate was carried out by diethylamine.